Pelvic Organ Prolapse (POP) and other associated pelvic floor disorders are among the fastest growing health concerns worldwide. POP affects 50% of all women who have given birth, and is the 2nd leading indication for surgery among women. Total US societal costs for treating and managing POP are over $29 Billion.
POP is characterized by the loss of structural integrity of the supporting tissues (muscles, ligaments, tendons, etc.) within the female pelvis. As the support tissues weaken, pelvic organs (vagina, bladder, rectum, and bowel) begin to protrude in to the vaginal canal and towards the vaginal opening. This leads to numerous complications including urinary and fecal incontinence, pain and ulcerations, sexual discomfort, and many psycho-social complications.
The most common cause of POP is childbirth. As the baby's head passes through the vaginal canal, the pelvic tissues undergo extreme stretch, pressure, and other potentially injurious conditions. This can lead to different injury mechanisms including, but not limited to: obstetric laceration for tearing of tissues or nerves, nerve fiber crushing, obstruction of blood flow to vaginal tissues leading to temporary ischemia, and levator muscle trauma. The risk of these injuries is increased by many factors such as obesity, previous injury, small maternal anatomy, large fetal weight and/or head size, and the presence of underlying connective tissue disorders. These injuries may be severe enough to cause POP symptoms shortly after childbirth. The more common scenario occurs as a progressive degenerative process. Muscle and nerve injuries sustained during childbirth may take years to reach a symptomatic level. In particular atrophic weakening of muscles due to nerve damage, combined with a decrease in hormonal tissue maintenance associated with the onset of menopause, leads to a relatively abrupt shift from asymptomatic POP to highly symptomatic POP when surgical interventions are likely. This age-related scenario is why 11% of all women will require a surgery to correct their POP by age 65. Factors that increase risk for POP later in life include obesity, heavy-lifting, endurance or high-impact athletics, and other conditions which may greatly or repeatedly increase the patient's intra-abdominal pressure.
The underlying phenomenon of the POP pathology, the process that leads to symptomatic POP, and the surgical treatments that correct POP are all inherently mechanical or structural. The ability to evaluate the structure of the organs and tissues involved in POP is crucial to understanding, diagnosing, and treating this pathology. The most common diagnostic method for evaluating POP is a physical exam of the pelvis conducted by a physician or nurse along with the completion of a brief “scoring” system (the Pelvic Organ Prolapse Quantification system or POPQ) which stages the prolapse as grade 1-4. This system is quick and effective, but inherently subjective. Other diagnostic techniques include urodynamics testing, which involves filling and draining of the urinary bladder while measuring certain diagnostic parameters. Vaginal manometry is another common technique, in which a balloon is inserted into the vagina and inflated while pressure is tracked. A similar technique to vaginal manometry is employed to evaluate the structural competency of the anus and rectum, called anorectal manometry (ARM). These techniques all seek to evaluate the way lumenal tissues respond to specific loading conditions. These existing systems are limited by their ability to simultaneously track the magnitude of the load and the magnitude of the displacement of the structures they evaluate.
Current in vivo biomechanics methods limit the ability of researchers, and greatly limit the potential for application of biomechanics in day-to-day diagnostics/treatment for practicing clinicians. What is needed is a tool allowing researchers and physicians to perform in vivo biomechanics studies of the vagina or rectum (or any other lumenal tissues, as is relevant) in a manner that does not require an expensive, separate medical imaging system, and which produces objective data.